Drilling tools of the type described above are used for either solid drilling or for boring, profile facing or spot facing of predrilled bores. When drilling into solid material or when finishing pocket bores, the removal of chips may be aided by the use of a coolant and lubricant which emerges from the shank tip at a high pressure and washes the chips out of the bore by way of the chip groove. When the chip grooves are radially open, the chips which are forced radially outwards due to the centrifugal force of the tool rotating within the bore travel mainly along the wall of the bore. In pre-drilled bores, in the walls of which recesses such as pockets or cross bores are present, there is the disadvantage that the chips enter the recesses and cannot flow out anymore. The chips then have to be removed in a time consuming further step.
In order to avoid this disadvantage it is known (DE-A-40 33 877) in a drilling tool of the type described above to provide the tool shank with a close-fitting sleeve which extends from the tool head in the direction of the clamped end. The chip grooves and the inner wall of the sleeve thereby delimit channels through which the chips created in the drilling process are removed. Since the tool head radially protrudes over the circumference of the tool shank and therefore has a larger diameter than the inner diameter of the sleeve, in the known drilling tool the sleeve can only be mounted on the tool shank from the clamping end. In drills having a reinforced shank and in stepped drills the fitting of such a sleeve is not possible at all.
Based on this it is the object of the invention to develop a drilling tool and a method of production thereof, with which closed channels for removing chips can be provided for different types of drilling tools.